title: Safrole-DNA adduct in hepatocellular carcinoma associated with betel quid chewing.
abstract: Betel quid chewing, which contributes high concentration of safrole in saliva, is a popular oral habit in Taiwan. Safrole is a documented rodent hepatocarcinogen, yet its hepatocarcinogenic potential in human is not known. Here, we used LC/ESI-ITMS(n) and LC/QTOF-MS confirmed safrole-dGMP as reference standard to detect the safrole-DNA adduct in hepatic tissues from HBsAg-/HCV-seronegative hepatocellular carcinoma patients by (32)P-postlabeling. We first synthesized and confirmed safrole-dGMP by LC/MS. Two isomeric safrole-dGMPs were characterized as N(2)-(trans-isosafrol-3'-yl) deoxyguanosine and N(2)-(safrol-1'-yl) deoxyguanosine. This technique was able to detect hepatic safrole-DNA adduct in mice that were treated with safrole but not sensitive enough to detect safrole-DNA adduct in human samples. Using the nuclease P1 version of the (32)P-postlabeling technique, we detected the presence of safrole-DNA adduct in two out of 28 hepatic tissues from hepatocellular carcinoma patients, and only these two patients had a history of betel quid chewing lasting more than 10 years. From co-chromatography with the mass confirmed safrole-dGMPs, this safrole-DNA adduct was identified as N(2)-(trans-isosafrol-3'-yl) deoxyguanosine. These results suggest that betel quid-containing safrole might be involved in the pathogenesis of hepatocellular carcinoma in human beings and LC/MS has the potential to identify DNA adducts in clinical samples.
authors.affiliation: Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taiwan.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Chung
authors.forename: Chiu-Lan
authors.initials: CL
authors.lastname: Chen
authors.forename: Cheng-Chung
authors.initials: CC
authors.lastname: Wu
authors.forename: Shan-An
authors.initials: SA
authors.lastname: Chan
authors.forename: Chin-Wen
authors.initials: CW
authors.lastname: Chi
authors.forename: Tsung-Yun
authors.initials: TY
authors.lastname: Liu
mesh_terms: D000428:Alcohol Drinking; D000818:Animals; D001114:Areca / Q000737:chemistry*; D006528:Carcinoma, Hepatocellular / Q000139:chemically induced / Q000378:metabolism*; D002853:Chromatography, Liquid / Q000379:methods; D018736:DNA Adducts / Q000032:analysis* / Q000737:chemistry; D005260:Female; D006801:Humans; D007274:Injections, Intraperitoneal; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008409:Mastication; D051379:Mice; D008807:Mice, Inbred BALB C; D015394:Molecular Structure; D010761:Phosphorus Radioisotopes; D012451:Safrole / Q000008:administration & dosage / Q000032:analysis* / Q000737:chemistry; D012907:Smoking; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013624:Taiwan; D013997:Time Factors
chemical_list: D018736:DNA Adducts; D010761:Phosphorus Radioisotopes; D012451:Safrole